Electric switch



April 10, I l J, E CARLSON 4 1,954,440

ELECTRIC SWITCH Filed June 17,'1953 2 sheets-sheet 1 INVENTOR Jol-1N E. CARLSON,

ELECTRIC swITcH Filed June 1'7, 1933 2 Sheets-Sheet 2 `|NvENToR Patented Apr. 1o, 1934 ELECTRIC SWITCH John E. Carlson, Forestville, Conn., assigner to The Trumbull Electric Manufacturing Company, Plainville, Conn., a corporation of Connecticut Application June 17,1933, Serial No. 676,273

8 Claims. (Cl. 5500-163) My invention relates particularly to the contact mechanism of an electric switch.

One object of the invention is to provide a very simple but effective form of switch.

, A special object is to provide mechanism which can be cheaply made and can be very readily assembled.

Another object is to provide a switch which, for a given size and cost, will have a maximum safe current carrying capacity.

Another object is to provide a construction in which the movable switch member has a sliding or wiping engagement with the stationary contact when operated to open or close the circuit.

Another object is to provide a switch of the foregoing character which may be mounted in an enclosure or switch box of conventional type andV operated by means of an external handle.

In the form of construction shown the stationary contacts of the switch are in the form of flat plates secured to an insulating base. The movable switch member is also in the form of a flat plate carried by a special link, one end of which is guided in the base between the stationary contacts and the other end of which is connected directly to an actuating. crank shaft which is pivoted in the opposite sides of the box.

This crank shaft is adapted to be manually 0perated and may be provided with a spring to hold the switch in the closed circuit or open circuit condition, or it may be operated by means of a quick-make, quick-break mechanism connected directly or indirectly to the crank shaft. The movable switch contacts are preferably guided in grooves in the base or between shoulders projecting from the base.

Fig. 1 is a front view of a construction embodying one form of my invention, the box cover being 'shown open and broken away and the parts of the switch being shown in full lines in the open circuit or off position. The operating handle is switch in the closed circuit position.

Fig. 5 is a similar fragmentary view (omitting the box) and showing-the parts of the switch in two different positions intermediate the open circuit and fully closed circuit positions, one of the positions being indicated by dot and dash lines.

Fig. 6 is a detail edge view of one of the movable switch members and its carrying link.

Fig. 7 is an exploded perspective view showing parts of the switch mechanism.

The switch box 10 and cover 11 may be of any suitable character and provided with any suitable interlock or latch.

The insulating base 12 may. be formed of any suitable material and is adapted to be secured in the bottom of the box by a number of screws such as 13 in the usual manner.

'I'he crank shaft 14 is pivoted in opposite sides of the box and provided with an external operating handle l5 which may be integral therewith A spring 16 is also provided, so located as to hold i the crank shaft in either the openv or closed circuit position, as shown in Figs. 2 and 4, respectively.

The stationary contacts 17 and 18 and the movable switch member 19 are in the form of flat plates of suitable material. The plate 17 is se'- cured to the base by a screw 20 and carries a circuit terminal member 21.

The other contact 18 is secured to the base by a screw 22 which also serves to secure a fuse clip 23 for a fuse 24 provided the construction is to include fuses. The other end of the fuse is adapted to be held in the usual manner in the clip 25, to which is connected the other circuit terminal 26 in any suitable manner.

The movable contact member 19 is carried by a special link formed of two flat pieces of in'sulating material, each of which has a head portion 27 with an open notch 28 for the crank shaft, a

stem 29 and an offset end 30. These two members may be identical and may be punched or blanked from strips of insulating bre or the like.

The movable contact element or unit includes two of the insulating link members, a contact plate 19, a spring 32 and a washer 33 and these parts may be readily assembled by first placing the two link members atly together with the hook ends projecting in opposite directions and with the washer 33 in position against the shoulv ders 34, 34 on the links. Then the spring is slipped over the ends of the links against the washer. The ends 30, 30 of the links are then passed through the hole 31 on'the plate 19until theI shoulders 35, 35 on the links have passed, through the hole in the plate and when the parts are released the pressure of the spring 32 Y will force the plate 19 down against the shoulders 35, 35 on the links and thus secure the five parts together as a unit which may be handled in practically the same manner as a single part.

Although the movable contact element is assembled as a unit for convenience in manufacture andas a matter of low cost, the parts are not permanently secured together but may readily be dis-assembled without tools by anyone who is familiar with the details of the element and its original assembly.

When thus assembled, it will be noted that the oppositely disposed hook portions of the insulating connectors form a complete circular bearing for the crank shaft from which connection they can not be removed except by aspecial manual manipulation.

In assembling a switch in a box, the crank shaft 14 is first wiggled through its bearing opening in the right hand side of the box (as viewed in Fig. 1) and the short end of the crank is then snapped into its bearing opening at the left hand side of the box. Then each of the required number of movable contact elements is taken in turn and held at right angles to its normal operating relation to the crank shaft in which position the free ends of the insulating hook members may be separated sufficiently to allow them to be passed at opposite sides of the shaft until .the slotted portions of the hook members are in line with the shaft. The contact unit may then be twisted or twined clockwise at right angles or, in other words, back to its normal relation to the crank shaft and to the stationary contacts and it will remain in this position until it is deliberately removed by a manual reverse operation.

'I'he base on which the stationary contacts have already been mounted is then inserted in the box and, in so doing, the ends 30, 30 of each of the movable contacts are inserted in the corresponding guide slot 36 in the insulating base. The link or hook members of the movable contacts are freely movable laterally on the crank shaft at one end and the other ends have a comparatively free movement in the guide slots in the base, therefore it is a very easy matter to adjust the several parts and seat the base in its normal operating position after which the base may be secured by means of the usual mounting screws.

I preferably provide guide flanges 37 of insulating material integral with the base on opposite sides of the respective contacts 17 and 18 to serve as guides for the movable switch plates and to also serve as barriers or arc interrupters.

The switch is operated in the usual manner by throwing the switch handle 15 oif and on, as the case may require. When the switch is moved from the olf to the on position the switch link is tilted through the positions indicated in Fig. 5 so that the switch plate 19 engages the stationary contact plates 17 and 18 and then sildes downwardly along the surface of the contact plates, as indicated by the arrows, so that the contact portions are kept bright by the normal operating movement of the switch, thus assuring good electrical contact.

When the circuit is opened the switch members 19 slide in the opposite direction before leaving the stationary contact plates. The opening and closing movement may be augmented or accelw erated by spring action inthe usual manner.

I claim:

l. An enclosed switch including an insulating base having a guide recess open toward the front of the base, a pair of stationary contacts mounted on the front of the base and spaced apart from each other, an enclosing box, a crank shaft mounted in the box in front of the base, a switch member including an insulating link detachably connected at one end to the crank shaft and having its other end loosely guided in the recess in the base and a switch plate slidable on said link for engagement with the stationary Vcontacts.

2. An enclosed switch including a box having a cover, a switch base mounted in the box and having guiding recesses open toward the front of the base, a pair of spaced stationary contact plates mounted on the front of the base adjacent each recess, an operating member consisting of a. crank portion lpivoted in the opposite sides of the box and extending across the front of the base and having a handle portion extending outside the box, switch members independently connected to said crank shaft and having their free ends guided in said base recesses, each switch member consisting of a link having a spring pressed movable switch plate tiltably mounted thereon and adapted to connect the contact plates of one of the respective pairs of stationary contact plates.

3. In an electric switch, a base having a pair of stationary contact plates spaced apart from each other, a pivoted crank shaft, a link formed of two members connected to said crank shaft, each of said members being formed of a flat strip of insulating material having a. head portion with a slot open toward one edge and having a central stem and an offset rear end, the ends of the two members being offset in opposite directions of the center line of the link and a movable switch plate mounted on the stems of said members and adapted to electrically connect the stationary contact plates.

4. In an electric switch, an insulating base having a guide passage therein and an insulating guide wall projecting from each of the opposite sides of the passage, stationary switch contacts mounted between the said guide walls, an operating crank shaft extending across in front of the base, an insulating link having one of its ends connected to said crank shaft and the other end guided in said passage and a spring pressed switch member mounted to slide on said link and adapted to tilt therewith between said guide walls. l

5. In an electric switch, an insulating base having two guide flanges spaced apart from each other, stationary switch contacts mounted on the base between said anges, a crank shaft, an insulating link detachably connected to said crank shaft and a spring pressed switch plate mounted to slide and tilt on said link between said guide flanges for adjustable and sliding engagement with said stationary contacts.

6. As an article of manufacture, a switch member formed of two strips of insulating material each having a slotted head, a central stem and an oilset inner end, a. switch plate mounted on the stems and a spring on the stems interposed between the plate and the heads of the strips.

7. As an article of manufacture, a switch member formed of two strips of insulating material, each having a head at one end with a passage for an operatingl crank shaft and having an offset tip at the other end with a connecting stem, a washer and a switch member mounted on the combined Stems, and a spring' mounted on the stems between said switch member and said washer.

8. A movable switch unit of the character described comprising two resilient strips, each having a slot opening at one edge, the openings of t the slots in the two strips facing in opposite directions to permit the unit to'be readily applied 

